Not true about congenital hypothyroidism: March 2009
**Core Concept**
Congenital hypothyroidism is a condition where the thyroid gland fails to produce sufficient thyroid hormones in newborns, leading to impaired growth and development. It is often caused by a genetic mutation, thyroid dysgenesis, or thyroid dyshormonogenesis.
**Why the Correct Answer is Right**
The correct answer is related to the pathophysiology and diagnosis of congenital hypothyroidism. Thyroid dysgenesis is the most common cause of congenital hypothyroidism, accounting for approximately 80% of cases. It involves the abnormal development of the thyroid gland, which can be due to a failure of thyroid gland formation or an abnormal location of the gland. Neonatal screening programs are crucial in detecting congenital hypothyroidism, as early treatment with thyroid hormone replacement therapy can prevent long-term complications.
**Why Each Wrong Option is Incorrect**
**Option A:** This option may be incorrect if it contradicts the established facts about congenital hypothyroidism. However, without the actual option text, it's difficult to determine its accuracy.
**Option B:** If this option suggests that congenital hypothyroidism is caused solely by environmental factors, it would be incorrect. While environmental factors can contribute to hypothyroidism, congenital hypothyroidism is primarily a genetic or developmental disorder.
**Option C:** If this option states that congenital hypothyroidism is a rare condition, it would be incorrect. Congenital hypothyroidism is relatively common, affecting approximately 1 in 2,000 to 1 in 4,000 newborns.
**Clinical Pearl / High-Yield Fact**
The American Academy of Pediatrics recommends that all newborns be screened for congenital hypothyroidism within the first week of life. Early detection and treatment can prevent long-term complications, such as growth retardation, developmental delays, and intellectual disability.
**Correct Answer:**
(Note: The actual correct answer and options are missing, so I couldn't provide the final answer)